JavaScript Reference



Returns a string representing the number in exponential notation.
Returns a string representing the number in fixed-point notation.
Returns a string with a language sensitive representation of this number. Overrides the Object.prototype.toLocaleString() method.
Returns a string representing the number to a specified precision in fixed-point or exponential notation.
Returns an object literal representing the specified Number object; you can use this value to create a new object. Overrides the Object.prototype.toSource() method.
Returns a string representing the specified object in the specified radix (base). Overrides the Object.prototype.toString() method.
Returns the primitive value of the specified object. Overrides the Object.prototype.valueOf() method.

 Created by Mozilla Contributors and licensed under CC-BY-SA 2.5



Using the Number object to assign values to numeric variables

The following example uses the Number object's properties to assign values to several numeric variables:

var biggestNum = Number.MAX_VALUE;
var smallestNum = Number.MIN_VALUE;
var infiniteNum = Number.POSITIVE_INFINITY;
var negInfiniteNum = Number.NEGATIVE_INFINITY;
var notANum = Number.NaN;

Integer range for Number

The following example shows minimum and maximum integer values that can be represented as Number object (for details, refer to ECMAScript standard, chapter 8.5 The Number Type):

var biggestInt = 9007199254740992;
var smallestInt = -9007199254740992;

When parsing data that has been serialized to JSON, integer values falling out of this range can be expected to become corrupted when JSON parser coerces them to Number type. Using String instead is a possible workaround.

Using Number to convert a Date object

The following example converts the Date object to a numerical value using Number as a function:

var d = new Date('December 17, 1995 03:24:00');

This logs "819199440000".

Convert numeric strings to numbers

Number("123")     // 123
Number("")        // 0
Number("0x11")    // 17
Number("0b11")    // 3
Number("0o11")    // 9
Number("foo")     // NaN
Number("100a")    // NaN

 Created by Mozilla Contributors and licensed under CC-BY-SA 2.5